Ore-roasting furnace.



. E PATBNTEDMAR. 14, 1905. H. M. HEATH, G. MORRICE & R. L. J... GRUSS.

ORE ROASTING FURNAGB. APPLIOATIQNHLED s211113. 1902.

NTTED STATES 1:"atemtel March 14, 1905.

PATENT OFFTCE,

HORACE M. HEATH, OF NEWTON, MASSACHUSETTS, AND GEORGE MORRICE,

OF SONORA, AND ROBERT L. J. GRUSS, OF GENESEE, CALIFORNIA, AS- SIGNORS, BY DIRECT AND MESN E ASSIGNMENTSTO FRANK W. MCALEER,

OF NEWTON, MASSACHUSETTS.

oRE-RoAsTlNc-r` FURNACE.

SPECIFICATION forming part Of Letters Patent N0. 785,067, dated. March 14, 1905,

Application filed September 13, 1902.I Serial No. 123.220.

To a/ZZ whom, 721 'nt/ty concern/r Be it known that we, HORACE M. HEATH,

residing' at Newton, county of Middlesex,

State of Massachusetts, and GEORGE MORRIOE,

5 residing at Sonora, county of Tuolumne, and

ROBERT L. J. GRUss, residing at Genesee,

county of Plumas, State oi' California, citizens of the United States, have inventedan Improvement in Ore-Roasting Furnaces, of

I which the followingdescription, in connection with the accompanying drawings, is a specification, like Hgures on the drawings representing like parts.

In the treatment for the extraction' of gold I of that class of auriferous ores commonly known as N sulfurets e., auriferous ores containing sulfur or arsenic, or both-it is essential that such ores be freed from sulfur or arsenic, or both, before being subjected to the 2O chlorination process. This process of freeing the aurii'erous ores from sulfur or arsenic, or

both, which process is commonly referred to as oxidizing the ore, is commonly accomplished by placing the ore to be treated in the heated retort or oxidizing-chamber oi' a suitable roasting-i'urnace and causing a current oi' air to pass over or through the ore while in such chamber. If the retort is heated suHiciently, oxygen from the current of air passing over or through the sulfureted ore unites with the sulfur in the ore, forming sulfur dioxid or sulfur monoxid, which escapes in the form of gas. Where the oxidizing oi' the ore is accomplished by taking the oxygen directly from the air, as above described, it is necessary to heat the ore to a temperature exceeding 1,200O Fahrenheit in order to secure the best results, and even then it is necessary to subject the ore to the action oil the air for a 40 considerable length of time in order to complete the oxidation.

It is the object of our invention to provide a novel form of roasting-furnace wherein the auriferous ore to be treated may be completely oxidized in a comparatively short length of time and at a temperature much lower than is necessary in furnaces with which We are familial'.

In accordance with our invention we have provided a roasting-furnace having a heated oxidizing chamber or Hue, through which the auriferous ore to be treated is passed, and an oxygen-generating Adevice adapted to deliver oxygen to the said chamber or Hue. The ore thus passes through an oxidizing-Hue containing oxygen, and as a result it is necessary to heat the Hue only to a temperature of about 600O in Order to secure perfect oxidation. Moreover, by using oxygen instead of air for the oxidizing agent the process of oxidation is completed in a comparatively short space of time as compared with the time taken where air is the oxidizing agent.

In the preferred embodiment of our invention we arrange our oxidizing Hue or chamber in a vertical direction and give the same a sinuous or zigzag course. The ore to be treated is delivered to the upper end of the lsinuous or zigzag Hue and gravitates to the lower portion thereof, from which it is delivered into a suitable receptacle or bin, while the oxygen is delivered from thegenerator to the lower portion of the oxidizing Hue or chamber and passes upward through the same in the direction contrary to that of the descending ore. The sinuous or zigzag course of the Hue operates to thoroughly disseminate the ore in its passage therethrough, thus allowing tbe oxygen to reach every part of the ore. 30

In the drawings, Figure I is a vertical central section of our improved roasting-furnace. Eig. 2 is a section on the line X X, Fig. 1. Fig. 3 is a section on the line Y Y, Fig. I; and E ig. 4 is a detail of the oxygen-generator. 85

rIhe body 3 of the furnace may be of any suitable material, such as brick, and is provided at its lower portion with one or more combustion-chambers 4, in which any suitable fuelsuch as coal, oil, or gas-may be burned for the purpose of heating the oxidizing-Hue, as `hereinafter described.

Extending upward through the furnace is an oxidizing chamber or Hue 5, which is surrounded or partially surrounded by heatingchambers 6, which connect with the combustion-chambers 4, and through which the heated products of combustion from said chambers 4 pass to the chimney or smoke-stack 7.

The ore to be treated is fed into the upper Beneath the lower end of the oxidizing flue orchamber 5 are one or more closed bins or receptacles 11, into either one of which the roasted ore from the flue 5 may be discharged. W'e prefer to employ two such bins or receptacles, as herein illustrated, for when two bins are employed the roasted ore may be discharged from the iue 5 into one of the bins, while the other bin is open for the removal of the ore which has previously been discharged thereinto. As herein illustrated, the discharge of the roasted ore from the flue 5 into the bins 11 is controlled by a suitable valve 12, which has apertures or ports 13, adapted to register with either of the passage-ways 14, which lead into the lower end of the flue 5. The valve may be operated in any suitable way, and is herein illustrated as being connected to a suitable operating-lever 15 by means of a link 16. When the lever is in the position shown in Fig. 1, the ore is being discharged into the left-hand receptacle 11, and the right-hand receptacle may be opened for the removal of the ore which has been previously discharged thereinto. .By swinging' the lever to the left the right-hand port 13 is brought into register with the righthand passage 14, thus opening the valve into the right-hand bin 11.

20 designates a suitable oxygengenerator which is connected by a pipe 21 to the lower end of the flue 5 at 22. This oxygen-generator may be of any suitableconstruction, and

is herein illustrated as comprising a suitable retort 23, which may be heated from a furnace24. The cover of the retort is designated by 25 and is shown as beinghinged to the body of the retort at 26.

To hold the cover in place, a yoke 27 is employed, which has its ends bent inwardly, as at 28, to engage the ears or lugs 29 upon the body of the retort. A wedge 30, driven between the yoke and the cover, serves to securely hold the cover in position. To produce the oxygen, some suitable chemical, such as peroxid of barium, is placed in the retort 23 and the cover 25 is closed. The heat from the furnace 24 operates to drive off the oxygen from the chemicals, which oxygen passes through the pipe 21 and is delivered to the liue 5, as will be obvious.

Itis necessary that the ore in its passage vthrough the oxidizing flue or chamber be disseminated, and for this purpose we have chosen to give the iue a sinuous or zigzag course, as illustrated in Fig. 1. Yeiind the best results are reached by making the straight portions 5' of the iiue on an incline of substantially fortyiive degrees. This provides the requisite inclination to allow the ore to freely gravitate through the flue and at thesame time causes the particles of ore to tumble over each other and become thoroughly disseminated during their passage through the flue.

The flue 5 and the chamber 6 may be constructed in any practical way. As herein illustrated, the body portion 3 of the furnace is provided with a sinuous or zigzag opening through its center which, is divided by the partitions 30, of lire-brick or any other suitable material, into the central oxidizing-ii ue 5 and the exterior chambers 6. The upper ends of the chambers 6 open into the passage-way 6', which in turn communicates with the stack 7, and the lower ends of the chambers 6 open into one of the combustion-chambers 4, while the lower end of the other chamber 6 communicates with thc other combustion-chamber 4.

If desired, we will connect the two chambers 6 at intervals throughout their length by means of flues or passage-ways 60, as seen in Fig. 2, whereby both sides of the oxidizing-liuc 5 may be heated, even though combustion istaking place in only one of the combustion-chambers.

The operation of the furnace will be evident from the foregoing and is as follows: rlhe ore to be treated upon being placed'in the hopper 9 is continuously delivered into the upper end of the oxidizing-flue 5, through which it gravitates into one or the other of the closed receptacles 11, according to the position of the valve 12, the ore becoming thoroughly disseminated in its passage through the flue on account of the shape of the latter. As the ore gravitates through the oxidizing'- flue it comes in contact with the upward current of oxygen, which is delivered to the lower end of the flue through the pipe 21, as above described.

1t will be understood, of course, that the oxidizing flue or chamber 5 is heated to about 600.D Fahrenheit by the heated products from the combustion-chambers 4. The heated oxygen upon contacting' with-the descending ore unites with the sulfur contained in the ore, thus forming sulfur dioxid or sulfur monoxid, which escapes through the upper end of the flue in the form of gas. The ore as it is delivered into the receptacle 9 is entirely freed from sulfur or arsenic, or both, and is thus ready for the chlorination process. After one IOO IIO

' peroxid of barium is used it becomes necesof the receptacles 11, which receptacles, it will be understood, are normally closed air-tight, is filled with the roasted ore the valve 12 will be shifted to cause the ore to be deposited into the other receptacle. The filled receptacle can then be opened and the roasted ore removed therefrom during the time .that the other receptacle is being filled. The oxidizing process can therefore be carried on continuously withoutinterruption. The oxidizing-Hue is closed air-tight except at its upper end, where the ore is fed into it, and Ithe receptacle 9 is also made air-tight, so that there is no opportunity for any air to be admitted to the oxidizing-Hue.v The only gaseous material, therefore, which passes into the Hue is the pure oxygen which is delivered from the oxygen-generator, and by thus excluding all air from the oxidizing-Hue and delivering into it only pure oxygen the process of oxidation can be greatly facilitated.

Where peroxid of barium is used as the agent for producing oxygen, it is desirable to employ two generators, either one of which may be employed to produce oxygen and deliver the same to the Hue 5, and in the drawings the pipe 21 indicates a pipe leading from 2l and which communicates with the second generator, (not sho\vn,) similar to 20. Suitable valves 34 serve to connect either of thc generators with the Hue 5.

Two generators are employed,because where sary after one generator has been in use for a certain length of time to remove the cover thereof and allow the same to cool, this process resulting in recharging the chemical in the retort with the oxygen from the air. While one of the retorts is thus being recharged with oxygen the other is employed to furnish the oxygen to the Hue 5.

It will be understood that various changes may be made in the structure of the furnace without departing from the spirit of our invention, for, as we believe that we are the Hrst to devise a roasting-furnace in which pure oxygen is used as the oxidizing agent rather than ai r, we desire to claim the same broadly.

Having fully described our invention, what we claim as new, and desire to secure by Letters Patent, is-

l. In an ore-roasting furnace, an oxidizing- Hue having non-perforated sides and open to the atmosphere only at the upper end where it receives the ore to be treated, means to heat said Hue externally, a plurality of air-tight chambers-beneath said Hue, means to connect the lower end of said Hue with either of said chambers, and means to deliver oxygen to the lower end of the Hue above said chambers.

2. In an ore-roasting furnace, an oxidizing- Hue which is open at its upper end to receive the ore to be treated, a furnace to externally heat said Hue, a plurality of air-tight chambers beneath said Hue, means to connect said Hue with either of said cham-bers, and an oxygen-generator connected' to the lower end of the Hue and operating to deliver pure oxygen thereto.

3. In an ore-roasting furnace, atower having a vertically-extending zigzag passageway, two parallel partitions extending longitudinally of said passage-way and dividing it throughout its entire length into three separate Hues, of which the central one constitutes an oxidizing-Hue, a combustion-chamber communicating with the two outside Hues, an air-tight chamber beneath and with which the oxidizing-Hue communicates, and means to deliver pure oxygen to said oxidizing-Hue, the two outside Hues having communication with each other at a plurality of points throughout their length.

In testimony whereof we have signed our names to this speciHcation in the presence of the subscribing witnesses.

HORACE M. HEATH. GEORGE MORRIOE. ROBERT L. J. GRUSS. Witnesses to signature of Heath:

LoUIs G. SMITH, J oHN C. EDWARDS. Witnesses to signatures of George Morrice and Robert L. J. Gruss:

Jo MORRIS, E. A. B. HENDERSON. 

